Over the past forty years, businesses have sought to maximize efficiency by using various devices to automate data entry. In the important area of inventory management, in particular, the symbol reading device (e.g., barcode reader, barcode scanner or RFID reader) has greatly reduced the time and errors inherent to manual data entry. Symbol reading devices are often employed to decode barcodes. A barcode is a machine-readable representation of information in graphic format. Traditionally, a barcode is a series of parallel bars and spaces of varying widths (e.g., a linear barcode or 1D barcode). More recently, there has been an increase in the use of alternatives to the linear barcode, for example matrix codes (e.g., 2D barcodes, QR Code, Aztec Code, and Data Matrix) and Optical Character Recognition (OCR) have enjoyed increasing popularity as the technology advances. As used herein, the terms barcode, indicia, and code-symbol are intended in their broadest sense to include linear barcodes, matrix barcodes, and OCR-enabled labels.
Indicia readers (e.g., barcode readers) tend to fall into one of three categories: wand readers, laser scan engine barcode readers, and image sensor based barcode readers. Wand readers generally include a single light source and single photodetector housed in a pen shaped housing. A user drags the wand reader across a code symbol (e.g., a barcode) and a signal is generated representative of the bar space pattern of the barcode. Laser scan engine-based barcode readers typically include a laser diode assembly generating a laser light beam and a moving mirror for sweeping the laser light beam across a code symbol, wherein a signal is generated corresponding to the code symbol. Image-sensor-based barcode readers typically include multi-element image sensors such as CID, CMOS, or CCD image sensors and an imaging optic for focusing an image onto the image sensor. In the operation of an image-sensor-based barcode reader, an image of a code symbol is focused on an image sensor and a signal is generated corresponding to the code symbol. Image sensor elements may be arrayed in a line or in a rectangular matrix or area. Area image sensors capture a digital picture and use software algorithms to find and decode one or more symbols. Users of laser scanner engine-based barcode readers have been switching in increasing numbers to image sensor based barcode readers. Image sensor based barcode readers offer additional features and functions relative to laser scan engine based barcode readers. These features and functions result from image processing algorithms. The limits of which are typically based on the processing resources available from the device.
Virtually all thin-profile, hand-supportable, smart-devices (e.g., smart-phones) now have integrated cameras. Accordingly, numerous applications capable of utilizing the integrated camera for indicia reading have been developed for these devices. While these applications perform reasonably well for the casual user, they lack the features and functions present in dedicated devices. Illumination, aiming, stabilization, and focusing could all suffer when using a general purpose mobile imaging device for indicia reading. The lack of dedicated resources could slow performance and compromise efficiency in fast paced work environments.
Typical users want to carry only one device and will be reluctant to trade their smart-device for a scanner. A need, therefore, exists for an indicia-reading module with all of the features of a dedicated scanner device that can integrate with a smart-device without being bulky. Such a module could integrate internally or externally. If internal, the module would have dimensions allowing for seamless integration into the smart device and would be easy for the user to operate with one hand. To this end an indicia-reader module that integrates into the smallest area side of the smart device (i.e., narrow-edge integration) would operate much like a hand-held, remote control which most users know well. This integration, however, puts severe limitations on the design of such a dedicated image-based optical scanner module. Unique design approaches and construction methods must be combined to allow for such novel integration.